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Comment period

Project Macoma - Announcement Availability of Application and of The Necessary and Overriding Public Interest Determination

National Pollutant Discharge Elimination System (NPDES) Wastewater Discharge Permit

April 3, 2024 - May 2, 2024, 5 p.m.

We invite you to comment on the permit applications and our determination of necessary and overriding public interest.

The permit allows Project Macoma to send (discharge) processed oceanwater to the Port Angeles Harbor. Comments are due by May 2, 2024. 

The proposed pilot project would intake seawater via a barge moored at a Port Angeles Harbor dock. It would pipe the seawater to a treatment facility on land, and process and de-acidify the seawater before returning it to Port Angeles Harbor via the barge-based outfall system. The purposes of the proposed pilot project are to operate Ebb Carbon’s mCDR technology under real-world conditions, support scientific research and gather additional data to inform future deployments. This field trial is conservatively designed to remove 500 net tons of CO2 from the atmosphere per year and reduce ocean acidification locally.

The discharge at the boundary of the mixing zone might exceed the water quality standards for pH. Project Macoma provided information so that Ecology could conduct an analysis to determine if lowering of water quality is necessary and in the overriding public interest. Ecology has made a tentative determination that it is necessary and in the overriding public interest to permit the discharge. We are interested in your comments about this determination and we will not make a final decision until all comments have been evaluated.

You may view the documents for Project Macoma or visit the Water Quality Permitting and Reporting Information System (PARIS) website.


We regulate wastewater released from municipalities and industries using the National Pollutant Discharge Elimination System (NPDES) Wastewater Discharge Permit. This permit regulates wastewater that goes directly into lakes, rivers, Puget Sound, or the ocean (surface water). All wastewater must be treated and meet the applicable water quality standards before it goes into surface water to protect human health and aquatic life. Learn more about water quality individual permits.

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Comment online

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Comment by mail

Gayle Garbush
Southwest Region Office
PO Box 47775
Olympia, WA 98504-7775
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Aziz Mahar
Permit Writer

To request ADA accommodation, contact Ecology's ADA Coordinator by email at ecyadacoordinator@ecy.wa.gov, or call 360-407-6831, 711 (relay service), or 877-833-6341 (TTY). More about our accessibility services.